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N. Chari et al.

Non-dimensional Parameters of Insect Flight

Shyy et al. [5] gave a comprehensive literature survey of insect flight research for

MAV development and problem areas to be tackled. Some of the important features

highlighted by Shyy et al. are considered as guidelines for the design of MAVs are

as follows:

Non-dimensional Numbers (Relevant to Scaling Laws).

a.

Reynolds Number (Re) is the ratio of inertial forces to viscous forces.

R e = ^{ρBeff Uerf}

μ

(9.2)

where ρ is Air Density.

Beff

is the Mean chord length of the wing for insect flight study.

Uref

is Free stream velocity.

In hovering flight,

Uref

is the mean wing tip velocity that is the angular velocity.

θ

is full stroke amplitude (radians) for flapping.

w = 2πf

where f = ¹

T ^.

l is wing span semi span; T is time for one cycle of flapping;

f is the wingbeat frequency.

b.

Reduced Frequency.

K = ^{π fcm}

Uref

(9.3)

cm

is mean chord length of the wing.

f

is frequency.

iii.

Strouhal Number (St).

Strouhal Number = ^2fha

Uref

= ^{wing tip velocity}

Uref

(9.4)

where

f

is the flapping frequency,